Dental apparatus



June 5, 1962 M. SHARP 3,037,283

DENTAL APPARATUS Filed Aug. 25, 1958 3 Sheets-Sheet 1 INVENTOR.

MARTIN SHARP Z MM ATTORNEY June 5, 1962 M. SHARP 3,0 7,283

DENTAL APPARATUS Filed Aug. 25, 1958 3 Sheets-Sheet 2 INVENTOR.

MARTIN SHARP ATTORNEY June 5, 1962 SHARP DENTAL APPARATUS 3 Sheets-Sheet 3 Filed Aug. 25, 1958 INVENTOR.

MARTIN SHARP- a q @E ATTORNEY United States Patent 3,037,283 DENTAL APPARATUS Martin Sharp, 7906 Chandier Road, Philadelphia, Pa. Filed Aug. 25, 1953, Ser. No. 756,847 7 tjlaims. (Cl. 32-67) This invention relates to dental apparatus, and more particularly to dental apparatus for making inlays for insertion into one or more teeth of a patient, or for preparing the teeth for mouth rehabilitation, such as bridge a-butments.

In the past, the practice has been to take a set of X-rays of the patients mouth and, in accordance with the information revealed, to then drill out various portions of the teeth for which the inlays are to be made. Impressions of the drilled out tooth areas are then taken, from which the inlay is made. Since some time is required in order to cast or otherwise form the inlays, temporary fillings are placed in the patients teeth so that normal mouth functions will not be interfered with unduly until such time as the inlays themselves may be fitted into the teeth. When the inlays are ready, the patient must then return to the dentist and have the temporary fillings removed so that the inlays may be placed in the teeth. If any extensive amount of inlay work is required, for example work involving a large number of teeth, it is the usual practice to drill only a few teeth at a time and to make the inlays for these teeth, before proceeding to further inlay work on other teeth. As a consequence, a number of visits to the dentist are generally required and can entail a great loss of time to the patient from his normal schedule of activity, such lost time frequently representing an appreciable amount of inconvenience.

By the use of the apparatus according to my invention it is generally possible to limit the required number of visits to the dentist to only two. On the first visit, the dentist takes a set of mouth X-rays and also an impression of the upper and/ or lower set of teeth in the patients mouth. At this time, no drilling of the patients teeth whatever is done so that the normal mouth functions remain completely intact and the discomfort and annoyance of temporarily filled teeth is eliminated. From the mouth casts the dentist may construct a model, and the teeth of the model may then be drilled out according to the information revealed by the X-rays. From the drilled-out teeth of the model, the inlays themselves may be prepared. Upon the return of the patient to the dentist, the patients teeth may be drilled in exact conformance with the drillings in the model, and hence the inlays prepared from the model will fit precisely into the patients teeth and may be installed as soon as any given tooth has been so drilled. It will be appreciated that the precision of fit of the inlay into the teeth of a patient is much greater when the necessity of removing a temporary filling is avoided. This is because such removal entails further dental drilling and the drilling of necessity, at least somewhat, changes the shape of the inlay cavity and therefore a perfect fit with an inlay made from an impression cannot be obtained. Accordingly, it is a primary object of my invention to provide novel dental apparatus for performing dental inlay work which does not require that a patient be subjected to a double drilling of his teeth by eliminating the necessity for using temporary fillings.

Another object of my invention is to provide novel dental apparatus for performing dental inlay work by which a near perfect fit between an inlay and the drilled out cavity of'the inlay receiving tooth may be achieved.

Still another object of my invention is to provide novel dental inlay apparatus the use of which substantially reduces the required number of visits to the dentists ofiice by a patient.

Yet another object of my invention is to provide novel "ice dental inlay apparatus which is easy to use, positive in its results, and effects a monetary saving to both the patients and the dentist by enabling the saving of a substantial amount of time as compared to that required for the carrying out of inlay work by presently used methods.

These and other objects will become clear from a careful reading of the following specification when taken in conjunction with the several drawings, wherein:

FIGURE 1 is a plan view of the apparatus according to the invention illustrating the drilling out of the teeth of the patient in accordance with the model made from the patients mouth.

FIGURE 2 is a side elevational view of the apparatus of FIGURE 1 taken along the lines 22 of that figure.

FIGURE 3 is a sectional view taken along the lines 3-3 of FIGURE 2 and showing certain pivot and carriage details of the apparatus.

FIGURE 4 is a side sectional view taken along the lines 44 of FIGURE 1.

FIGURE 5 is a side sectional view taken along the lines 5-5 of FIGURE 4 and illustrating certain pivot and carriage construction details.

In the several figures, like elements are denoted 'by like reference numerals.

Referring now to the figures and firstly to FIGURE 1, it will be seen that the apparatus according to my invention consists essentially of three functional units, a supporting stand or mount 20, a carriage 21, and a unity ratio pantograph including three arms 22, 23, and 24, connected to the carriage 21 by a three dimensional pivot system. Fixedly secured to the right-hand side of the stand or mount 20 by a pair of screws 25 is a model 26 of a set of lower teeth of a patients mouth. Some of the teeth, as for example the teeth 27, 28 and 29, have been drilled out in accordance with information obtained from a set of X-rays, and impressions taken from the drilled out teeth of the model have been used to make a set of inlays to be inserted in the corresponding teeth in the patients mouth.

Immediately to the left of the dental model 26 is seen a portion of the lower jaw of the patient from which the model 26 was made, so that the set of lower teeth shown therein conform exactly in size, shape and relative position to the teeth of the model 26. The teeth 27', 28', and 29' in the patients jaw correspond therefore to the teeth 27, 28 and 29 in the dental model 26. It is the function of the dental apparatus illustrated to enable the dentist to drill the teeth 27, 28' and 29 in exact conformance with the drillings of the corresponding teeth in the dental model 26, and hence provide perfect receptacles for the inlays made from the impressions taken from the drilled teeth of the dental model. In order that the drilling of teeth 27, 28' and 29 shall be in exact conformance with the drillings in the teeth 27, 2,8 and 29, it is required that the patients jaw be held immovable relative to the model 26 during the drilling process. To this end, several clamping devices are employed. One possible clamping system is illustrated in FIGURES 1 and 4- and includes a chin rest 30 (illustrated in FIGURE 4) secured to the amount 20 by a bracket 31 and a pair of machine screws 32. Adjustably securable to the mount 20 by screws 3% is an arm 34, and pivotally securable to the arm 34 at its fore end by a nut and bolt 35 are a pair of arms 36 and 37. To the fore end of the arm 36 is fastened a tooth clamp 38, and to the fore end of an arm 39 pivotally connected to the arm 37 by a nut and bolt iii, is a tooth clamp 41.

The arm 34 is adapted for longitudinal and lateral shifting by the provision of the arm slot 42 and the slots 43 in the mount 20. Positioning of the arm 34 is accomplished by loosening the screws 33 and shifting the arm 34 longitudinally and laterally to the desired position, and then retightening the screws "33 to hold the arm 34 securely in position. The tooth clamp 38 and the tooth clamp 41 are grossly adjusted over the teeth to which they are to be clamped by the foregoing described positioning of the arm 34. Final positional adjustments of these clamps is achieved by pivoting the arms 36, 37 and 39 about their pivots and 4-9, after which the clamps are applied to the underlying teeth. Head straps or other devices, none of whch are shown, may also be employed if considered necessary. Finally, in order that the entire apparatus does not have to be supported by the patients jaw a support arm 44, a fragment of which is shown integrally formed with the mount 20, may be clamped to the dental chair so that the latter supports the weight of the apparatus and carries it along with the dental chair when any chair motion occurs.

Turning now to a consideration of the carriage 21 which carries the unity ratio pantograph, it will be seen that the mount 20 is formed with a central raised portion 45 of generally rectangular shape which contains a pair of longitudinally extending grooves 46. Adapted to ride in the grooves 46 are a set of four Wheels 47 which are rotatably secured to the carriage 21 by bearing screws 48, the heads of which seat on the top surface of the carriage 21 and the threaded ends of which secure into turned under ears 4-9 at the four corners of the carriage 21. These details of the carriage construction are best seen in the views of FIGURES 2, 3 and 5, and particularly in the views of FIGURES 3 and 5.

The wheels 47 allow the carriage 21 to ride longitudinally on the mount 20 so that the fore end of the pantograph arm 23 may be positioned relative to various teeth in the model 26. The wheels 47 are so positioned within the grooves 46 that the carriage 21 is restricted in its motion relative to the base mount 20 to purely longitudinal travel, and has no rotational motion about any axis whatever. Such restriction of motion of the carriage 21 is provided so that the motion of the pantograph to be now described may be precisely controlled.

The function of the pantograph including the arms 22, 23 and 24 is to enable a dental drill 50, secured to the arm 22 by a pair of knurled locking screws 65, to exactly follow the movements of the tracing arm 23. At the fore end of the tracing arm 23 is a feeler pin 51 which traces the inside surface of the cavities drilled in the teeth of the dental model 26. As shown in FIG- URES l and 2 the pin 51 is positioned within the inlay cavity of the tooth 28. The position of the feeler pin 51 controls the position of the drill bit 52 mounted at the fore end of the drill 50, and since the pantograph is designed for unity arm ratio, a given displacement of the feeler pin 51 always causes an identical displacement of the drill bit 52 In this way, it can be seen that as the feeler pin 51 traces out the outline and depth of the cavity in for example the tooth 28, the drill bit 52 will drill an identical cavity in tooth 28 of the patients mouth.

The pivoting arrangement of the structure which conmeets the pantograph arms 22 and 23 to the carriage 21, together with the method of connecting the arm 24 to the arms 22 and 23, allows three dimensional rotation of the feeler pin 51 and drill bit 52. This three dimensional rotation together with the longitudinal shifting of the carriage 21 is required in order to accurately follow the surface of the inlay cavity drilled in the teeth of the dental model 26. Horizontal rotation of the pantograph arms is provided by a double-cone pivoting arrangement which is best seen in FIGURES 3 and 5. In FIGURE 3, the tracing arm 23 is pivoted to an F- shaped link 53 by the cone pivots 54. Vertical plane rotational motion is provided by pivoting the link 53 to a link 55 by employing a second set of cone pivots 56. Links 57 and 59, and cone pivots 58 and 60 of FIGURE 5 bear a one-to-one correspondence to the links 53 and 55, and cone pivots 54 and 56 of FIGURE 3, and provide the same rotational freedom for pantograph arm 22 as is provided for arm 23.

The horizontal and vertical pivot structures of FIG- URES 3 and 5 just described operate in synchronism through the action of the pantograph arm 24 which interconnects the arms 22 and 23. The arm 23 connects to the arm 24 through a ball and socket joint 61, and the arm 22. connects to the arm 24 through a ball and socket joint 62, these connections being visible in FIG- URES 2 and 4 respectively. Although the foregoing described horizontal and vertical pivoting motions can just as readily be achieved by securing the arm 24 to each of the arms 22 and 23 by a pivot pin, the use of such a pivot pin would prevent rotational motion of the arms 22 and 23 about the axes defined by the cone pivots 63 and 64 shown in FIGURES 2 and 4 respectively. The cone pivots 63 pivotally connect the link 55 to a vertically extending ear of the carriage 21, and the cones 6:3 pivotally connect the link 59 to a similar ear extending vertically from the carriage 21.- The combined effect of the cone pivots 63 and 64 together with the ball and socket joints 61 and 62 is to permit a lateral rolling motion of the arms 22 and 23 so that outwardly tapering inlay cavity surfaces may be readily followed.

Although my invention has been described in connec tion with particular apparatus for practicing the same, it will be understood, of course, that such description is for illustrative purposes only, and various changes and modifications may be made from time to time without departing from the general principles or real spirit thereof and it is intended to claim the same broadly as well as specifically as indicated by the appended claims.

What is claimed as new and useful is:

1. In dental apparatus, the combination comprising, a stand, means for securing a dental model to said stand, means for securing one jaw of a dental patient to said stand in a predetermined position relative to said dental model, a pair of spaced-apart coupled arms shiftably coupled to said stand so that said arms are shiftable as a unit relative to said model and jaw positionsfeach arm being provided with means for three dimensional rota tional motion of said arm means, intercoupling said arms so that all rotational motions of one are simultaneously performed by the other, means associated with one of said arms for scanning the surface of teeth mounted in a stand-secured dental model, and means for so securing a dental drill to the other of said arms that the drill bit will scan the surface of teeth in a stand-secured patients jaw which correspond in position to the teeth in a stand-secured dental model scanned by said scanning means, the tooth areas scanned by said scanning means and said drill bit being identically oriented relative to the respective teeth being scanned.

2. In dental apparatus, the combination comprising a stand, a carriage mounted on said stand and translationally shiftable relative to the latter, a three arm pantograph pivotally mounted on said carriage for translation therewith, two of said pantograph arms being held in parallel spaced relationship to one another and each being provided with means for three dimensional rotational motion by the pantograph pivotal mounting and the interconnecting third arm independently of the translationally shifted carriage position relative to said stand, said third arm being so connected to each of said parallel arms by a universal joint that the axial rotation of either parallel arm causes an identical axial rotation of the other parallel arm.

3. The dental apparatus of claim 2 wherein said pantograph pivotal mounting comprises a pair of independent pivoting devices each of which interposes said carriage and a different one of said parallel arms.

4. The dental apparatus of claim 2 wherein said stand for securing a dental drill thereto in such a way that the 10 movement of the drill bit tracks the movement of the said scanning means.

6. The dental apparatus of claim 5 wherein said scanning means is a feeler pin supported by said one parallel arm proximate one end thereof, said pantograph pivotal mounting comprises a pair of independent pivoting devices each of which is attached to a diiferent one of said paral lel arms, and said pivoting devices lie between the points of connection of said third arm with said parallel arms and the feeler pin and drill bit positions.

7. The dental apparatus of claim 5 wherein said scanning means comprises a mechanical sensing element adapted to follow the surface contours of drilled-out inlay cavities in the teeth of the dental model.

References Cited in the file of this patent UNITED STATES PATENTS 1,472,034 Asquith Oct. 30, 1923 2,793,569 Tanner et al. May 28, 1957 2,817,901 Freeman Dec. 31, 1957 

